Rosemary Benefits for Brain Health

Ancient Greek students ate rosemary to improve their memory. Some wore rosemary garlands when studying for exams, and others even braided garlands of the aromatic herb into their hair. Smoke from the burning of rosemary leaves was once recommended to prevent “brain weakness.” 

Can rosemary really improve memory and brain health? Is there sufficient evidence to support the use of rosemary for improving memory and other cognitive functions? 

In this article, we will discuss the potential benefits of rosemary for brain health and explore research findings from several preclinical trials and human studies.

Potential Rosemary Benefits for Brain Health: Pharmacological Properties of Rosemary

Rosmarinus officinalis L., or rosemary, is an evergreen bushy shrub that is native to the Mediterranean region. It is a perennial herb with needle-like leaves and has a somewhat bitter flavor. 

While it is most well-known for its use in cooking, food preservation, and cosmetic applications, rosemary has a rich history of non-food and non-cosmetic uses. Proposed medicinal properties of rosemary include:

• Antibacterial (prevents growth or spread of bacteria)
• Antioxidant (prevents or delays some types of cell damage)
• Anti-apoptotic (prevents apoptosis, a type of cell death)
• Anti-inflammatory and antinociceptive (reduces inflammation and blocks the detection of painful stimulus)
• Anti-thrombotic (reduces the formation of blood clots)
• Antidiabetic (prevents or alleviates diabetes)
• Anti-epileptic (prevents seizures)
• Anti-cancer (arrest or prevents cancer)
• Neuroprotective (prevents neuronal cell death)
• Mitoprotective (prevents mitochondria from damage)
• Antiulcerogenic (prevents the onset of ulcers)
• Hepatoprotective (prevents damage to the liver)

Among these, the most notable potential benefits of rosemary for brain health are its neuroprotective, mitoprotective, and antioxidant properties. Preclinical studies have attributed these benefits to the various types of diterpenes present in rosemary. In particular, the diterpene, carnosic acid, has been the main area of focus. 

Potential Rosemary Benefits for Brain Health: A Look at the Research

Over the past several decades, we have seen many theories proposing that rosemary can improve memory and other cognitive functions, protect against brain injury, and have therapeutic potential for neurodegenerative diseases like Alzheimer’s disease. However, evidence supporting such theories primarily comes from studies involving animal models and very small human studies. 

Here’s a quick look at the research surrounding the benefits of rosemary for brain health:

Human Research:

• A 2012 randomized, placebo-controlled, double-blind, repeated-measures crossover study of 28 people (with a mean age of 75) aimed to investigate the possible effects of dried rosemary leaf powder on cognitive performance. They reported a biphasic dose-dependent effect in measures of speed of memory; the lowest dose (750 mg) of rosemary had a statistically significant beneficial effect compared with placebo (P=.01), whereas the highest dose (6,000 mg) had a significant impairing effect (P<.01).
• A small 2009 open-label study of 28 people with dementia (with a mean age of 86.1) reported that aromatherapy (rosemary and lemon essential oils in the morning, lavender and orange in the evening) for 28 days was associated with improved personal orientation related to cognitive function. However, due to the variety of ingredients involved in this study, it is not possible to attribute the reported benefits to a specific ingredient such as rosemary.

While no robust evidence exists for humans, a handful of preclinical studies suggest that carnosic acid may protect against brain injury and improve learning and memory.

Animal Models: 

• In a mouse model of traumatic brain injury, carnosic acid treatment (1 mg/kg) 15 minutes after controlled cortical impact injury significantly preserved mitochondrial respiratory function and decreased oxidative damage to mitochondrial proteins..
• In a mouse model of Alzheimer’s disease (hAPP-J20 mice), transnasal carnosic treatment (10 mg/kg) for three months was associated with improved learning and memory (in vivo). In vitro, this treatment reduced dendritic spine loss in rat neurons exposed to oligomeric beta-amyloid.

While there is some evidence to suggest rosemary may benefit the brain, more research is needed to better understand the effects in humans at scale. Due to the lack of substantial evidence of rosemary’s benefits for brain health in humans, it is unlikely that consuming or smelling rosemary alone can prevent cognitive decline and substantially improve cognitive function. 

If you want to ward off cognitive decline or boost cognitive function, you may consider incorporating well-researched Alzheimer’s and dementia prevention strategies. In general, experts recommend:

• Quitting smoking
• Exercising daily (30-60 minutes/day)
• Eating a heart-healthy diet
• Getting adequate sleep
• Minimizing stress
• Controlling alcohol consumption